Balancing system for aircraft.



J. P.'TARBOX.

BALANCING SYSTEM FOR AIRCRAFT. APPLICATION FILED AUG-15.1912- RENEWED FEB. 5. I917.

2 SHEETS-$HEET l- I I WITNESSES Patented Sept. 11,1917.

J. P. TARBOX. BALANCING SYSTEM FOR AIRCRAFT. APPLICATION FILED AUG. 15. 1912. RENEWED FEB- 5.1917.

Patentdfiept. 11, 1917.

2 SHEETS-SHEET 2 "ma ma.

JoHiv P. 'rnnnox, or

BUFFALO, NEW YORK, ASSIGNOR TO TARBOX SAFETY AIRCRAFT COMPANY, A CORPORATION OF DELAWARE.

BALANCING SYSTEM FOR AIRCRAFT.

Application filed August 15, 1912, Serial No.'715,275.

To all whom it may concern:

Be it known that LJOHN P. TARBox, a citizen of the United States, residing at Buffalo, New York, have invented a new and useful Improvement in Balancing Systems for Aircraft, of which the following is a specification.

My invention relates to a stabilizing or balancing system for air-craft adapted to give the craft on which it is installed an inherent balancing action. As I shall show it herein, the system is essentially independent of the main supporting surfaces of the craft, and being thus independent is capable of being installed on any known type of air-craft without modification. However, instead of being thus embodied, the system of myinvention may include lifting surfaces other than those shown, and forming' part of or an adjunct to the main sup porting surfaces of the air-craft, without departing in anywise from the spirit of my invention.

As a preliminary to a more detailed description which will lead to the broad definition of my invention, it may be stated that the embodiment herein described comprises an aeroplane device having itself an inherent balance and of the type commonly termed kites. This type of aeroplane devices has long been known to possess inherent stability. The particular form herein disclosed has been invented by applicant and is constituted by two lifting surfaces, each alone being one half of the kite, one being mounted at each lateral extremity of the craft for free balancing movement about a vertically extending axis fixed to the craft, or other frame transversely co-extensive therewith. These lifting surfaces are connected with the axesat points insuring for mstance, as points 1n-' this action, such wardly displaced and forward of the center of pressure as is usual in connecting cords to independently flown kites, or else devices may be attached to the lifting surfaces which give to them this balancing action, such for instance, as tail-vanes, weights or r the equivalent.

-.The se oppositely disposed lifting surfaces constituting the halves of the kite structure, are connected together for balanclng movement in unison about their vertically ex tending axes,

simple link or cord connection between the the connection shown being a Specification of Letters Patent.

Patented sept. M, 19117..

Renewed February 5, 1917. Serial No. 146,860.

axes, with the result that though separated they have a balancing action identical with that of the ordinary kite which is known to possess inherent balancing action. 'In other words by dividing the lifting surfaces of the kite in the manner stated, I have given the kite an efiective spread (by which I mean in this case the lateral over-all dimensions) equal to or greater than the spread of the craft and have not impaired its balancing action. It is evident, of course, that I might use a single kite pivotally connected to a centrally located vertically extending axis and having a spread equal to the spread of the craft, but it is patent that such an arrangement would be decidedly more cumbersome although it would possess substantially the same balancing action.

In combination, my invention further comprises a vertical rudder, or equivalent means, operating in unison with the kite surfaces in their balancing movements to correct variation in head resistance of the craft caused by the balancing movements. And in order that the air-craft may be satisfactorily banked while making turns, the system includes a shifting device for shifting the relative normal positions of 'the lifting surfaces with respect to the craft, without impairing their free balancing action about their vertically extending axes. In this embodiment the shifting device comprises means for varying the relative lever- 'age of the cord connection between the axes of the lifting surfaces. This means is connected to be operated whenever the vertical rudder is moved to make a turn.

Additionally, manually operable means are provided for destroying the automatic action of the balancing system just described, and effecting hand "operation of the balancing kite surfaces whenever desired.

The drawings are diagrammatic views showing the system as installed on an aircraft in perspective.

Figure 1 is a view of the elementary system without means for banking, and means for manual operation. This system may be used as shown in Fig. 1, especially when. other provision is made for banking the craft. Also some craft do not need provision for banking, as they bank themselves.

Fig.2 is a view of the complete system.

Referring'first to 1, L, L, are lifting surfaces constituting the opposite halves of the kite. Each lifting surface is mounted on a vertically extending axis 10 at any suitable angle thereto,.at a lateral extremity of the air-craft, the axis being free to turn in upper and lower bearings 11, which bearings are preferably of the ball-type whereby the axis turns with a practically negligible friction. The point 12 of attachment of the lifting surface to the axis 10 is nearer the inner end 13 of the surface than the outer end 14, and is also preferably nearer the entering or forward edge of the lifting surface than the trailing edge. In this way there is always an over-balancing pressure on the outer end 1214l tending to move that end inwardly.

Rigidly connected to the axis 10 at any suitable point, preferably near one of the main supporting surfaces of the craft, as shown the lower supporting surfaces, are longitudinally extending cross-bars 15. The front ends of these cross-bars are connected by a transversely extending cord 16, and the rear ends similarly connected by a cord 17, the points of connection being in each case equi-distant from the axes, whereby the free balancing movement of the surfaces L, L, is not restricted when they move from normal position. As shown, their normal position is the position in which the lifting surfaces are oblique to the longitudinal axis of the craft with their inner ends pointing forwardly, the normal angles of inclination of the two lifting surfaces to the longitudinal axis being equal.

On the rear ends of the cross-bars 15 are provided adjustable weights 18, and similarly adjustable vertical tail-vanes 19.

Connected to the cord 17 by means of cords 20 is an auxiliary vertical rudder 21, operable through the connections 20 in unison with the lifting surfaces L, L in their balancing movements. A hand-lever 23 and connections 24 are shown for operating the main rudder 22.

For the control of the elevation of the craft, is shown a tail-plane 25 of parabolic section hinged at its entering edge to the frame 26 of the craft, and operable from lever 27 by'means of cords 28 connecting through a system of levers 29 with the plane. A spring 30 is connected atone end with the lever 29 and at the other end adj ustably connected to the frame 26 (by movement along the same). This also is a feature of my present system.

In operation, assuming the craft to tilt to the right, immediately due to the preponderance of weight to the rear of the axes 10, both the weights 18 and the weight of the plane ends12-14 being eflective, the balancing devices swing in unison counterclockwise, looking down upon the top of the craft. Thus the lifting surface L is brought more nearly into a transverse position whereby its lifting force is increased, and the surface L'is brought nearly into a longitudinal direction, whereby its lifting forceis decreased. Thus there is an increase in the lifting force on the lower side of the craft and a decrease of lifting force on the higher side of the craft, with the result that the balance of the craft is restored automati callya The surfaces L, L in this balancing action move counter clockwise (or clockwise if the unbalancing is opposite) until the increase in head resistance on the end 12-14 of the surface L is suflicient to counter-act the deflecting force of the weights 18 and the longer ends 12-14 of the surfaces. This is the usual balancing action of the independently flown kite. The vertically extending vanes 19 when moved out of their normal plane augment or increase the head resistance on the ends 12-44, and in addition constitute means whereby this may be adjusted. They furthermore serve as damping vanes and act to damp undue oscillation of the lifting surfaces of the kite, an opposing force being set up when they are deflected in either direction from the longitudinal. They may or may not be used, as is also the case with the weights 18, but I prefer to use both for the purpose of adjustment. For this purpose the size of the vane and the mass of the weight need be comparatively small, and in fact diminutive as respects the size and mass of the surfaces L, L. This is particularly true of the vanes 19. Thus, the degree of movement of the surfaces L, L occasioned by unbalancing force is always approximately proportional to the unbalancing force irrespective of the force of gravity, since the surfaces L, L and weights 18 are balanced as respects gravitational action as long as themachine remains horizontal (whichit'does until its inertia is. overcome by the unbalancing force) seriously disturb this approximation of proportional corrective movement. Obviously,

and the vanes 19 are too small to both may be located at some other point and kite surfaces L, L take. place, as has been observed, the head resistance is increased on one side of the craft, the lower decreased on the high side. This affects the craft as-a whole. The connection 20'to the auxiliary rudder 21 effects operation of the rudder 21 in a direction to counteract the side, and

. nection 16 between the lifting surfaces turning movement brought about by this variation in head-resistance.

Referring now to Fig. 2, wherein the complete system of my invention is shown, it will be seen that instead of making the cop,-

to fixed points on the bars 15, the connection is made to movable points constituted by sliding blocks 31. A cord connection extending radially from the axes 10, 10 is provided for operating these blocks 31 simultaneously in opposite directions whereby the relative leverage of the connection 16 to the surfaces L, L may bevaried. Commencing with the left-hand surface L this cord connection starts at block 31 and passes over a vertically arranged pulley 32 and beneath block 31 to the right of a loose pulley 33 on axis 10 and to the left around a laterally displaced idler-pulley 34 fixed to the frame 01'- the craft, and to the right of the craft as cord 35 around the rear of idler-pulley 33' on the right axis 10, and forward beneath block 31 around the vertically arranged pulley 32 and to block 31 on the right of the craft. From this block 31 again, the connection extends to the left of the upper idler-pulley 36, and to the right and around the laterally displaced idler-pulley 3 1, and to the left of the craft as cord 37 and around the rear of idler-pulley 36 on the left axis 10, and forwardly to the left-hand block 31. The cord 37 is connected by means of oppositely disposed bell-crank levers 38 to the connections 24: of the main vertical rudder 22 which is operable through lever 23 as in Fig. 1.

Now when the rear rudder is operated in one direction or the other the bank of the craft is primarily effected and regulated by the balancing system. Through the cord 37, and the connections just traced, one of the blocks 31 is moved outwardly on its bar 15, while the other is moved inwardly. For instance, suppose the rudder 22 is moved to the left to make a left turn, the cord 37 is thereby moved to the right. By this movement it will be noted that the left block face L, therefore,

31 is moved inwardly, while the right block 31 is moved outwardly from the axes 10, 10 respectively. The over-balancing head resistances of the ends 12-14 of thelifting surfaces L, L, are equal or else the kite would not be innormal position. Under these conditions, however, they are not other, one acting on the other through an increased lever- The end 12-44: of the left lifting surin the case assumed, acts through the proximate block 31, the connection 16 and the removed block 31 of the right lifting surface L to effect a counterage.

, clockwise rotation of the lifting surfaces,

until the increased head resistance of the end 1Q1t of the right-hand lifting surface L change of leverage,

lifting surfaces in a ously the banking left-hand surface L. Therefore there is brought about on the right-hand side of the craft an increased lifting force, due to the approach of the surface L to the transverse position, and that side of the craft is raised, thus banking the craft for the lefthand turn. The natural banking effect of difi'erence in speed of the extremities 'of the craft is thus supplemented and regulated.

The connections at and 37 may be made of any desired ratio whereby the banking may be adjusted to suit any desired conditions of any craft. Obviously, once the balancing devices have adjusted themselves to a new normal position as a result of the they exercise from that normal position a free and unrestricted balancing action as before. Thus they act to prevent banking of the craft beyond the point warranted by the deflection of the vertical rudder 22, the weights 18, etc, acting to cause reverse movement when the banking passes beyond a predetermined point, and it should be noted that as the craft takes its banking position, the counteracting force of the weights, 18, etc., returns the surfaces L, L, toward normal position. Thus when the banking is for a left turn as assumed, the right-hand of the craft being up in response to a counterclockwise movement of the lifting surface as described, the weights 18 as the craft becomes banked assisted by the increased head resistance of surface L, return the clockwise direction to their original normal positions, and further to suchpositions as will counteract any tendency ,to bank beyond such point as war ranted by the deflection of the main rudder 22. The action is altogether similar when the craft is banked for a right turn. Obviconnections may or may not be used as desired, depending upon the characteristic of any particular craft. If used the, connections could indeed be reversed, should the extreme tendency of any given craft to banking of its own accord warrant it, in that event opposition to banking would be initially set up.

It should be noted that the connections 35-and 37 are so 33' and 36, 36 t at in the movement of the blocks 31, 31 there is produced no effective turning moment on the axes 10, and thus the free balancing movement of the kite surfaces L, L is not even at this time restricted in any way.

In connection with the cable 16, there is assed around the idlers 33,

provided a hand lever 38 for manually and different arrangement, and that they have an automatic balancing action in their normal operation, and not in any wise akin to that of the manually operable devices referred to.

In combination with this automatic lateral balancing system, is provided the automatic fore and aft balance described in connection with Fig. 1, the parts in Fig. 2 are similarly numbered. When rising from the ground the elevating plane 25 is controlled by hand through the lever 27. After rising the lever 27 'is released altogether, and the control is automatically efi'ected through the variation in pressure on the rudder 25.

' The rudder is a lifting surface due to its parabolic section. It is pivoted at its front .edge, or at another point forward of the center of pressure, and its lifting force is pitted against! the spring 30. Obviously when the speed of the craft increases, the

' lifting force increases, and as a result the rudder 25 is moved upwardly, thereby decreasing its lifting force, and resulting in.

a lowering of the tail-end of the craft. Similarly, upon the decrease of speed the lifting force is decreased and the rudder 25 descends, thus raising the tail-end of the craft by the accompanying increased lifting force. Thus when the craft descends at too abrupt an angle due to longitudinal unbalancing and the speed is increased, the lifting force on rudder 25 is increased with the result that it is deflected upwardly and lowers the tail-end of the craft, thus' decreasing the abrupt angle of descent. Thus, also when the speed is below normal, as when the craft is pointed upwardly at too great an angle, the lifting force on plane 25 is decreased, with a resulting descent of the plane, and a raising of the tail of the craft which decreases the angle of ascent of the craft and brings it back to normal. The action of descending and ascending currents on the surface 25 is similar. Thus the craft is wholly automaticin its balancing movements and may be said to possess an inherent balancing action.

Other means of fore and aft control may be used.

The embodiment of my invention which I have described is the best form now known to me, but my invention is capable of many other embodiments without departing in any wise from its generic spirit. Even the embodiment which I have shown, may be such changes may be most readily made by" those skilled in the art, and all fallwithin the scope of my invention, I intendto cover in the annexed claims.

Two points have not yet been mentioned and should have special note. In the first place it is pointed out that the vertical rudders and the horizontal controlling plane 25 may both be mounted in advance of the mainplanes of the craft after the manner of the vertical and horizontal planes in the Voisin aeroplane, the craft being provided with a head instead of a tail. WVhen so mounted their passage, with-the action of the wind upon the rudders, is more regular and uniform, being free from the swirls and eddies of the propeller blast. This is of considerable importance in connection with the auxiliary vertical rudder connected with the kite system so also the uniformity and regularity of the wind action on theautomat1c balancing surface 25 is conducive to a smoother action.

It is to be noted that applicant is privileged to adjust the center of gravity of the aircraft as a whole by any of the wellknown means such as moving the power unit, the addition of weights at the nose or tail, or the like, with a view to adjusting the load carried by the horizontal tail unit 25.

Cords 28 are connected to a lever located at any suitable point, preferably adjacent to the control levers 23 and 27 as indicated in Fig. 2. By means of them the collars 30 and the springs 30 connected with them latter made to conform to any desired condition of speed of the machine or load lift ofthe horizontal tail unit 25. \1 It is obvious that any desired type of horizontal control may be used instead of that disclosed.

What I claim is:

1. The method of correcting the effects of unbalancing forces on aircraft, which consists (1) in setting up irrespective of the force of gravity the corrective forces in response to unbalancing forces before the craft becomes unbalanced and approximately pro- .may be adjusted and the tension of the portional to the unbalancing force, after 1,23e,csc

force of gravity the corrective forces in response to unbalancing forces before the craft becomes unbalanced and approximately proportional to the unbalancing force, (2) after the craft becomes unbalanced supplementing the corrective force previously set up to a value approximately proportional combinedly to the then value of the unbalancing force and. the existing degree of unbalancing of the craft, (3) maintaining the latter proportion of the corrective force until the craft is returned to normal position.

3. The method of correcting the effects of unbalancing forces on aircraft, Which consists (1) in setting up irrespective of the force of gravityv the corrective forces in re-' sponse to unbalancing forces before the craft becomes unbalanced and approximately proportional to the unbalancing force, (2) after the craft becomes unbalanced supplementing the corrective force previously set up to a value approximately proportional combinedly to the then value of the unbal ancing force and the existing degree of unbalancing'of the craft, as unbalancing force due to difierence in supporting pressure is removed decreasing the latter corrective force approximately proportionally thereto, but (4) maintaining the proportion of said corrective force to the degree of unbalancing of the craft until the same is returned to normal position.

4:. The method of correcting the effects of unbalancing forces on aircraft, which consists (1) in setting up irrespectvie of the force of gravity the corrective forces in response to unbalancing forces before the craft becomes unbalanced and approximately proportional to the unbalancing force, (2) after the craft becomes unbalanced supplementing the corrective force previously set up to a value approximately proportional combinedlyto the then value of the unbalancing force and the existing degree of unbalancing of the craft, (3) as unbalancing force due to difierence in supporting pressure is removed decreasing the latter corrective force approximately proportionally thereto, but (4:) maintaining the proportion of said corrective force to the degree of unbalancing of the craft until the same is returned to normal position, and (5) artificially creating an unbalancing force When it is desired to bank the craft.

5. An aircraft comprising a main su porting member which constitutes the li ing body of the craft, a balancing device located upon each side of said main support-- ing member and presenting cooperating lifting surfaces forming a salient angle rear- Wardly, said balancing devices being connected, and each responsive to temporarily preponderating head pressure, to increase the lifting moment of the other.

6. An aircraft comprising a main supporting member which constitutes the lifting body of the craft, a balancing device upon each side of said main supporting member and presenting cooperating surfaces arranged to be normally acted upon in flight by air pressure to produce torques in opposite directions about the longitudinal axis of the craft, said balancing devices being connected to each other and each responsive to temporarily preponderating pressure thereon to increase the torque of the other.

7. An aircraft comprising a main supporting member Which constitutes the lifting body of the craft, a balancing device upon each side of said main supporting member 80. and presenting cooperating transversely extending surfaces arranged to be normally acted upon during flight by air pressure to 1 produce torques in opposite directions about the longitudinal axis of the craft, said balancing devices being connected to each other and each responsive to temporarily preponderating pressure thereon, to increase the torque of the other.

8. An aircraft comprising a main supporting member which constitutes the lifting body of the craft, a balancing device upon each side of said main supporting member and presenting cooperating transversely extending lifting surfaces arranged to be acted upon normally during flight by the air rush to produce torques in opposite directions about the longitudinal axis of the craft, said balancing devices being connected to each other and each responsive to temporarily 10o preponderating pressure thereon to increase the torque of the other.

9. An aircraft comprising a main supporting member which constitutes the lifting body.of the era-ft, a balancing device upon each side of said main supporting member and presenting cooperating surfaces arranged to be normally acted upon in flight by air pressure, to produce torques in oppo-' site directions about the longitudinal axis of the craft, said balancing devices being connected to each other and each responsive to temporarily preponderating pressure thereon to increase the torque of the other, but each acted upon by gravity When the craft is unbalanced to increase its oWn torque.

10. An aircraft comprising a main supporting member which constitutes the liftin'g body of the craft, a balancing device upon each side of said main supporting member and presenting cooperating pivotany mounted surfaces arranged to be actthe other, and further having a normally inactive but preponderating mass acting upon one side of each of their pivots. I

11. An aircraft comprisin a main supporting member which constitutes the lifting body of the craft, a balancing device pivotally mounted on each side of said main supporting member and presenting a preponderating lifting surface disposed laterally of the pivot thereof from the longitudinal axis of the craft, the said balancing devices being further connected together and having a preponderating mass onthe same side of their pivots as the preponderating lifting surfaces, whereby the devices are moved in unison about their pivots by the combined action of gravity and the air rush.

12. An aircraft comprising a main supporting member which constitutes the lifting body of the craft, a balancing device upon each side of said main supporting member and presenting cooperating surfaces arranged to be normally acted upon in flight by air pressure to produce torques in opposite. directions about the longitudinal axis of the craft, said balancing devices being connected to each other and each responsive to temporarily preponderating pressure thereon to increase the torque of the other, and a damping vane connected with said balancing devices and acted upon by the air rush when the surfaces move from theirthereon to increase the torque of the other,

and steering means for the craft-connected porting member which constitutes the lifting body of the craft, balancing devices,

opposite directions as respects a determinate axis of the craft, said balancing devices being connected to each other and each responsive to temporarily preponderating pressure thereon to increase the torque of the other, steering means for the craft, and torque varying means associated'with said surfaces and connected with said steering means for operation thereby. I

15. An aircraft comprising a main supporting member which constitutes the lifting body of the craft, a balancing device upon each side of said main supporting member and presenting cooperating surfaces arranged to be normally acted upon in flight by air pressure, to produce torque in opposite directions about a determinate axis of the craft, said balancing devices being connected to each other and each responsive to porting member which constitutes the lifting body of the craft, a balancing device upon each side of said main supporting member and presenting cooperating surfaces arranged to be normally acted upon in flight by air pressure, toproduce torque in opposite directions about the longitudinal axis of the craft, said balancing devices being connected to each other, and each responsive to temporarily preponderating pressure thereon to increase the torque of the other, steering means for the craft, connections between said means and the aforesaid system of elements arranged to efiect operationof the same to bank the craft when the steering means is operated.

, JOHN P. TARBOX.

Witnesses JAMES H. MARK, CHAS. S. GRUMMAN. 

